From JP 2009 299261 a device suitable to regulate both in height and in the longitudinal direction a door or leaf connected to a carriage sliding in a rail is known of. Such device comprises a box, attached to the sliding door, consisting of a plurality of components connected together and provided, along the inner and outer vertical walls with multiple horizontal, vertical and oblique through cavities. By means of screws and pins which are made to slide in said cavities the movement of the sliding door is achieved to perform the adjustment required.
WO2011 161707 relates to a system for the height adjustment of a retractable sliding door, which is moved by means of carriages. Said latter are coupled to respective supports by a screw the rotation of which causes the relative movement between said elements and the consequent height adjustment of the door.
EP 2 243 913 also describes a support for sliding doors with means for height adjustment. Such means comprise a threaded element which engages with a worm screw, in turn engaged with a helical gear. By acting on the worm screw the helical gear and, consequently, the threaded element is placed in rotation; the latter, rotating, changes the positioning in height of the door.
There are also brackets with lateral adjustment, i.e. performed starting from an open face of the sliding rail, but in this case too the problem arises of the attachment using tools of said brackets in the upper part adjacent to the rail and the space between the latter and the hanging element thus remains high. According to another known solution, on one type of bracket it is possible to perform locking but not lateral adjustment; to achieve the latter it is necessary to remove the door or leaf from the relative bracket. This is, however, on the whole, a rather imprecise adjustment, now rejected by the manufacturers of sliding doors.
A further drawback which is found in relation to the sliding elements in question concerns the possible recoil incurred at the end stroke and which sometimes determines dangerous oscillations in the vertical direction and a high level of noise.